Engine starter



March 9,1926 1,575,698

W. L. MCGRATH 4ENGINE STARTER" FildAugust 2, 1919 2 sheds-sheet 1 yMarch9, 1926. '1,575,698

w. L. MCGRATH ENGINE STARTER yielding driving connection, and secondtolPatented Mar'. 9, 1926.

UNITED STATE-s 1,575,698 vPATENT OFFICE.

WILLIAM L. MCGRATH, OF ELMIRA, NE-W YORK, ASSIGNOR TO ECLIPSE MACHINECOMPANY, OF ELMIRA. NEW YORK, A CORPORATION O F NEW YORK.`

ENGINE STARTER.

Application led August 2, 1919. Serial No. 314,952:

vsuch as the liy Wheel of the engine to be started. The' object of myinvention is to improve andmake practical that type ofK drive in whichthe automatic shifting move- 'ment of the driving membervor pinion intoengagement With the engine member 1s accomplished by the employment of apair of coacting spiral gears, one of-Which is a driving gear drivenbythe starting motor either directly or indirectly, andthe other a drivengear mounted .for axial or longitudinal movement along the driving gear.The particular objects of my invention are first to provide this type ofVdrive with .a

provide the drive with means forl holding the driven'gear in normalposition and to prevent re-meshing, which means is also capable ofenforcing longitudinal lmovement of such driven gear when beingautomatical y moved axially or longitudinally.' .Other features ofadvantage and utility 1n my construction of drive will 'be apparent fromthe description hereinafter given.

In the drawing Fig. 1 is a sectional elevation of an engine starterembodyingmy in-V vention, thisparticular construction being of theout-board type; Fig. 2l a sectionalelevation on a modiied form ofconstruction illustrating the in-board type; and F ig.v 3 a ldetail viewof a modified form.

Referring to 'the particular embodlment of .myl invention as shown inFig. 1 the electric starting` moto-r indicated at 1 is provided with laniarmature shaft' 2 bearing in and extended beyond the end plate 3,attached to the motor frame in suitable manner as by bolts 4.' Thisplate 3 is provided with a laterally projecting-lnackct 5 'teiminatingat its outer end in a bearing G and also. constitfuting a partialhousing for the drive below.

Upon this extended armature shaft' 2-there is secured a spiral gear 7which is therefore driven or rotated by the starting motor.

This gear meshes and coat-.ts with a complementary spiral gear S whichis mounted loosely and adapted to slide. longitudinally upon asupporting shaft 9. This shaft'is supported at its inner end in theplate 3 and at its outer end in the bearing 6 to which latter it issecured in suitable manner as by .means of the pin 10. The gear 8 isprovided with an outwardly extending hub 11 inwhich is mounted the means-for holding the gear .8 inv its normal position axially with respect toits supporting shaft. These means comprise in the present instance aplunger 12 reciprocating through a radial opening in the hub 11 andprojected inwardly into the bore of such huband into a circumferentialgroove 13 in the shaft 9. This plunger is spring pressed by means of thecoil spring 14C- bearing at its lower end against a collar lseeured tothe .plunger and against a bracket 16 secured to and projecting from theouter face of the gear 8. The groove 13 and the plunger are so locatedthat they coact at the time when the gear 8 is in its normal or homeposition illustrated in Fig. l. This plunger or spring pin isnotpermitted to contact with the bottom of the groove but only With a side`thereof for reasons hereinafter explained. The driving member is'here inthe form of a pinion 17 adapted to engage with the teetlrlS of thefiywheel 19 ofthe engine such as'an internal combustion engine. Thispinion is loosely mounted on the shaft 9 so as to slide and also rotatethereon.. The shaft ismade of two diameters, the pinion being mountedon'the larger diameter. The pinion is vprovided with aninwardlyextending hub 20 and the two hubs 11 and 20 are operativelyconnected by a yielding driving connection 'which is here a coiled drivespring 21 Whose opposite ends are secured to said hubs by the anchorVstuds 22 and 23 respectively. At. the shoulder24 formed at the junctionbetween the two diameters of the shaft 9 I locate an antivfrictionbearing 25 against which the hub result that the gear 8 will beautomatically 110 moved along its shaft 9 to the right and the pinion 17will be correspondingly moved longitudinally and into mesh with theflywheel gear.` then the electric` motor is thus started theacceleration is suoli as to jump the plunger or spring pin out of thegroove 13 and permit said longitudinal movementof the parts. llhislongitudinal movement is assured by reason of t-he fact that the plungerl2 is in frictional contact with the surface of the shaft 9 whereby anytendency of the driven gear 8 to rotate is retarded.

-In such eases as might so require means may be provided kon thesupporting shaft t) to further accentuate this effect such as thelongitudinal corrugation QG as illustrated in Fig. 3.

After the pinion 17 is in mesh with the flywheel gear and itslongitudinal move-ment is arrested by Contact of the hub .ll against thebearing 25, the gear 8 will rotate and such rotary motion will becommunicated through the drive spring to" such pinion which latter willthereupon rotate the ilyivheel. lVhen the motor starts on its own powerthe assembly of pinion spring and spiral gear S are of course caused torotate at a higher rate of speed than they are driven by the drivinggear 7 and the demeshing will therefore automatically occur in the usualmanner. By the provision of the plunger the gear 8 will be retained inits normal or home position and remeshing is prevented even though thearmature and gears continue to rotate. that the plunger does not contactthe bottom of the groove but only the side thereof, since contactingwith the bottom would tend to resist rotation of the gear 8 and increasethe tendency to longitudinal movement, whereas contact with the side ofthe groove prevents longitudinal movement of the gear on account of itsstate of rotation.

`In Fig. 2 I have shown a modified form of construction in which thecorresponding parts are similarly numbered. In this con. struction thespiral gearing on the gears 7 and 8 run iu an opposite direction` .tothat shown in Fig. l with the result that the assembly of driven gearspring and pinion will be automatically moved to the left along thesupporting shaft when meshing with the Hywheel gear. This represents theiii-board type of drive inasmuch as the pinion moves inwardly towardsthe motor when meshing` with the flywheel gear.` In this constructionthe anti-friction bearing 25 is located at the inner end of the shaft 9so as to be contacted by the .inner end of the inner side of the gear Fiwhen in operating position.

I In both forms of Construction, the drive spring permits ofthe relativelongitudinal It will be noted movement of the pinion and driven gearwhich is desirable for meshing purposes.

I claim:

l. An engine starter drive Vcon'iprising a driving spiral gear, a secondspiral gear driven thereby, an engine driving member adapted to be movedautomatically into operative engagement with a member, of thev engine tobe started andto thereupon drivey such engine member, a shaft on whichlsaid driven gear and said driving member are loosely mounted, for bothrotary and longitudinal movements, a driving connection between saiddriven gear and said driving member, and means initially tending to holdthe pinion against longitudinal movement and thereafter to assure suchmovement and prevent rotary movement thereof on the shaft.

2. An engine starter drive comprising a driving spiral gear, a secondspiral gear drven thereby, an engine driving member adapted to be movedautomatically into operative engagement with a member of the engine tobe started and to thereupon drivesuch engine member, a shaft on whichsaid driven gear and said driving member are loosely mounted, for bothrotary and longitudinal Infovements, a driving Connection between'saiddriven gear and said driving member, andineans initially tending to holdthe pinion against longitudinal movement and thereafter to assure suchmovement and prevent rotary movement thereof on the shaft, such meansconsisting of a spring pressed plunger moutned on Athe driven gear and agroove in the shaft adjacent the normal position of the driven gear, theplunger normally being .positioned in the groove but adapted to`frictionally engage the shaft after the driven gear has movedlongitudinally.

3. An engine Starter drive comprising a driving spiral gear, a secondspiral gear driven thereby and having a hub, an engine driving memberadapted tobe moved automatically into operative engagement with a memberof the`engine to be started and to thereupon drive such engine 'member ashaft on which said driven gear and said driving member are looselymounted for both rotary and longitudinal movements, said shaft being oftwo diameters with a dividing shoulder andv with the driving member onthe larger diameter, an anti-.friction bearing at such shoulder againstwhich bearing said gear hub abuts in the driving operation, and yieldingdriving connection between said driven gear and said driving member.

, WILLIAM L. MoGlL/Vlli.

